Vibration reduction system using impedance regulated active mounts and method for reducing vibration

Abstract

A vibration reduction system including a base, a disturbance generating device, and at least one active mount connecting the base and disturbance generating device for imparting a force at a point on the base to minimize the transmission of the disturbance to the base. The active mount includes a passive element on which the disturbance generating device is supported, an actuator for imparting a force on at least the base, a sensor located on the base for sensing the total force imparted by the active mount at the selected point and generating a corresponding signal, and a controller for generating an input signal corresponding to the force to be imparted by the actuator on at least the base and sending the input signal to the actuator. The controller regulates an impedance error as a function of the signal received from the sensor to generate the input signal. The force imparted by the active mount at the selected point on the base substantially counteracts the disturbance applied to the base by the disturbance generating device. The active mount further includes a second sensor located on the base for detecting a velocity or acceleration of the base at the point on the base. The invention also includes a method of reducing vibrations of a base caused by a disturbance generating device mounted on the base via an active mount.

What is claimed is: 
     
       1. A vibration reduction system comprising: a base;   a disturbance generating device that causes a disturbance in the base; and   a plurality of active mounts, connected to the base and the disturbance generating device, for imparting forces at points on the base to minimize transmission of a disturbance to the base from the disturbance generating device, each of said active mounts including: a passive element, connected to the base, that supports the disturbance generating device,   an actuator that imparts a force on at least the base,   a sensor, connected to the base, that senses a total force imparted by the active mount at a respective one of said points and generating a signal representing the total force, and   a controller that regulates an impedance error as a function of the force signal from the sensor, the controller generating an input signal based on the regulated impedance error to control the actuator to impart a force on at least the base, said force imparted by the active mount substantially counteracting the disturbance in the base caused by the disturbance generating device.     
     
     
       2. The vibration reduction system according to claim 1, wherein said force imparted by the active mount includes said force imparted on the base by the actuator and a second force caused by the disturbance generating device through the passive element. 
     
     
       3. The vibration reduction system according to claim 1, wherein each of the active mounts further includes a second sensor located on the base for detecting a velocity or acceleration at said point on the base. 
     
     
       4. The vibration reduction system according to claim 3, wherein the controller further regulates the impedance error as a function of the velocity or acceleration detected by the second sensor. 
     
     
       5. The vibration reduction system according to claim 1, wherein the controller further regulates the impedance error as a function of a measured impedance. 
     
     
       6. The vibration reduction system according to claim 5, wherein said measured impedance represents an impedance imposed on the base by said active mount and by said disturbance generating device. 
     
     
       7. An active mount for reducing vibrations on a base caused by a disturbance generating device, comprising: a passive element that supports the disturbance generating device and imparts a first force on the base;   an actuator that imparts a second force on at least the base;   a plurality of sensors, connected to the base, that detects a total force imparted on the base by the passive element and by the actuator, and that detects a velocity or acceleration of the base; and   a controller that generates a signal to control the actuator to exert the second force on the base, said controller regulating an impedance error of the active mount as a function of the force and the velocity detected by the sensors to generate the signal, said second force imparted by the actuator substantially counteracting the vibrations on the base caused by the disturbance generating device through the passive element.   
     
     
       8. A method of reducing vibrations on a base caused by a disturbance generating device mounted on the base via an active mount, the active mount including a passive element and an actuator, the method comprising: imparting a force from the actuator on at least the base;   detecting a force imparted by the actuator and by the passive element on the base;   calculating an impedance value representing an impedance imposed on the base by the active mount and by the disturbance generating device;   regulating an impedance error as a function of the impedance value and the detected force; and   generating a control signal to control the force imparted by the actuator to reduce the vibrations on the base.   
     
     
       9. The method of reducing vibrations according to claim 8, further comprising detecting a velocity or acceleration of the base. 
     
     
       10. The method of reducing vibrations according to claim 9, wherein the impedance error is also regulated as a function of the detected velocity or acceleration of the base. 
     
     
       11. The method of reducing vibrations according to claim 8, wherein the imparting of force from the actuator on the base further includes exerting a force from the actuator onto the disturbance generating device. 
     
     
       12. A method of reducing vibrations in a base caused by a disturbance generating device mounted on an active mount above the base, the active mount including a passive element and an actuator, the method comprising: detecting a force imparted on the base by the actuator and by the passive element;   detecting a velocity of the base;   measuring an impedance;   regulating an impedance error equal to said force detected on the base plus the measured impedance multiplied by the detected velocity of the base; and   generating a control signal to vary a force imparted by the actuator on the base so as to reduce the vibrations in the base.   
     
     
       13. The method of reducing vibrations according to claim 12, further including imparting a force from the actuator on the base. 
     
     
       14. The method of reducing vibrations according to claim 12, wherein said measured impedance represents an impedance imposed on the base by the active mount and by the disturbance generating device.